Means for unloading air-compressors.



No. 865,390. PATENTED SE31. 10, 1907! E. HILL.

MEANS FOR UNLOADING AIR GOMPRESSORS.

APPLICATION FILED MAY 24. 1907.

PATENTED SEPT. 10, 1907.

E. HILL, MEANS FOR UNLOADING A UGMPRESSQRS,

MPLIUATIOH FILED my 24. 1907.

0L 6% A a w 9v A/ ip w @W UNlTED STATES.

EBENEZ'ER HILL,IOF NoitwALK, CONNECTICUT.

MEANS FOR UNLQADING n'm-oomrnnssons.

Specification-bf Letters Patent. Application filed May 24; 1997. Serial No- 375.432-

Patented Sept. 10, 1907.

To all whom it may concern:

.Be it known that I, EBENEZER HILL, a citizen of the United States, residing at Norwalk, in the county of Fairfield and State of Connecticut, have invented a new and useful Means for Unloading Air-Compressors, of which the following is a'specification.

This invention relates to a means designed to automatically operate to unload or relieve an air compressor of a part, or the whole of its work, according to the degree of the pressure in the reservoir, receiver or system into which the compressor is forcing air. I

The object of this invention is to provide an un loading means which will partially unload .or relieve -a compound air compressor without disturbing its mechanical balance or decreasing the relative efiiciency oi the compressor.

I cooler. 2 0

The invention is illustrated in connection With-a double-acting compound air compressor with an intercarried in the intercooler between the cylinders the pressure in the intercooler resulting from the fact that the second cylinder is not as large as the first cylinder, and that as the air irom the first cylinder must all pass through the second cylinder it must be reduced in bulkand thus its pressure increased.

If the first cylinder, by anysystorn of unloading, does not take and forceforward its full normalsupply of air,

and at the same time there is not a proportionate unloading of the second cylinder, the pressure in the intcrcoolcr will fall, and the best conditions of the working of the compressor will be sacrificed. On the other hand, if the second cylinder only is partially unloaded, so that it will not take in'andforce iorward a full normal supply of air, the intercooler pressure will rise and the compressor will not operate under I the most efiicicnt conditions.

By means of the apparatus which forms the subjectof the present invention both cylinders are unloaded proportionately at the same time; that is'ii the first cylinder is unloaded one-half, thev second is also unloaded one-half; and this keeps the work done by each cylinder properly proportioned and the pressure in the intcrcooler the same as when both cylinders are fully loaded and are accomplishing a maximum amount of work.

In the form of the invention illustratcdwhen'both cylinders are fully loaded the forward and return strokes during each revolution consume the same power, as the cylinders are double-acting, consequently when the first cylinder is half unloadeda by rendering For any given pressure of discharge from the i one side of the cylinder ineffective, the complementary half of the second cylinder is unloaded at the same time, that is, if the first cylinder only works on the forward stroke, the second cylinder will 'onlywork on the return stroke, thus preserving the mechanical balance of work-during each complete revolution.

In-the views, Figure 1 shows a portion of a compound double-acting air cornpressor provided with apparatus which embodies this invention, .the said apparatus being; arranged to operate upon intake valv'es of the ever, is not essential to the invention, it only being necessary that there be an independent unloaderior each end of'each cylinder and that the unloaderson' the complementary ends of each cylinder be controlled at the sametime or by the same control. Fig. .2 shows a sectional view of one of the air'control valves 'hwellwknov'vn' Corliss type. The type oi valves, how

used in this apparatus.- Fig. 3 shows a section of a i valve controlling mechanism used with this invention and its relation to the intake valves at opposite ends of'on'e cylinder." Fig. 4 shows a sectional view of the valvecasing of an air control. 5 shows a plan of the'valvc casing. Fig. 6 shows a sectional view of a portion of an air control And Fig. 7 shows a sid elevation of an air control valve. s

In thecompressor shown the large or first cylinder 1 is connected with the small or second cylinder 2 by means of .th eintercooler 3. The pistons. in these cylinders are joined in the common manner and are connectedwith the cross-head 4 which is reciprocated in the ways 5 by the usual engine mechanism. The

' first cylinder has Corliss intake valves 6 and 7, which i are actuated'by the crank or eccentricrodS, and the I second cylinder has similar intake valves 9 and 10, wliiclnare tictnated by the crank or eccentric rod ll.

When the machine is operating under normal con-' gditions is taken inby the first cylinder and forced through theintercooler to the second cylinder and then forced'il'om the second cylinder through the discharge pipe 12 to .the receiver or reservoir 13 of the system to be suppliedwith air under pressure.

A pipe 14 leads from the receiver to an air control 15 which opens when the pressure inthe receiver reaches I va predetermined degree. .And a pipe with a branch 16 leads from this air control to a mechanism 17'that is adaptod'to afiect the operation of theintakcvalve 6 at one end of the Iii-st cylinder. A branch 18 from the pipe loading from this air control connuu'nicatcs with a mechanism 19 that is arranged to affect the operation I of the intake yalve 10 at the opposite ondbfthe second cylinder. A bran'ch 20 leads from the outlet of the trols the effective action of the intake valve 7 ol the first cylinder. branch 24 leading from the outlet .rrol communicates with r n Eb-that coni ols the cll'ccti action of the "lgQj'Hi r'jllllllil es the first air control to open to actuate the wlvc confml 17 at one me time to actuate ihc va vc control at the other end of the -courl cylii 'he'n. mechanisms are ittnrltcil ivy *l c sir 'pircssuic t at cuter-s when rho rust cunt jlv cilfl,lil'llllillll()' nvcsonthcoppositeonds oi the firs :ml curl cvli 11's are hclrl opcn, 11ml (ll-s (lov'n tho cslozicitjv c1 lncu rlcgrw and allmvtl c curl of izlic iim:

ure frills suflicir y the nicclmnisrns 17 nd allow the votive-s to resume their the pressure rises.

've sci-ion. and is the "censure con- 1 iii at tho ctneroppositc thosc that were acnormal. elle tinues to Full the inechnni ends of the two cylinders, that mated first are relieved so that those two ends are ight into commission, .LllOWlll; me full non Lil effective operation ich of the vclve controls has cviiuii w "hich a. piston 27 with a stein 28 that 1-2 mic-pied to be retracted into the of the cylinder hy iill' pro When. the air pressure hack. of the high'te overcome ii-hcl oi tl l g the y- :1 Stem is thrust out so as in engage the lot 4h uid cause it to disconnect the valve stern arm 31 from the eccentric rocl arm 32 (Fig. 3), and their the rec v ecsteccenlric rod docs not actuate the valve, but leaves it open in the position it rmcupiecl .kvlicu the piston stein tri pcrl the hitch. Wh n the pi retracts the pi re compressor by a spring and forced nut 11:: back of the piston.

connect the valve sir-in arm mm the eccentrirfrcri arm so that the recipm'mtinn of the cor cause tlic valve to (JZJUIl and cloi unisni rnsry' H mm: reriwh'] This column i907, togclher with its action on the valve opcratin mechanism, will consequently is-uot described mor 11 detail herein. I l

As previously stated the air-- pressure is 1.11mi tied to tlre several. cylinrtion of the air controls referred to,

Each 01' the air controls above mentioned has in :1 case 3P a y hen the pr currin the row ivr rczrchcs a pro \"o,lvo controls.

ston is sufficiently of the valve controls by we zrc- 'lindriczrl valve 34J1hnt is normally held to Z1, scat 35 by the pressure efu spring 36 on a steinllliin the upper end of the air controL, In tbspositienthe h i A i I 1 L p p the other com lcmentary theiorce o thcspring the valve is lifted and-moved into such'position r thut air can pass through the scat, around the valve, and through the outlet 40 to which is connected the discharge pipe, that is, the pipe which leans to the At the some time that the valve is lifted from the inlet seat it is closed against ii sent 41 so as to prevent leakage through the casing whi h holds the stem and spring, and also so as to relieve the upper end of the valve of the pressure which is exerted on the lower end which assists in overcoming the thrust of the spring and renders the valve more sensitive. When the pressure drops sufl'iciently for tho spring to close the valve the air in. the pipes beyond the discharge outlets from the air controls, escapes by leakage and illlons the springs to retract the valve control plungcrs and their stems which prevent the intake valves from operating normally. This air control is substantially tiresome as that shown and described in the Patent No. 844,802 above referred to.

When the first air control which is c0nnect:d with the air receiver opens it unloads the distant ends of the large cylinder and. the small cylinder. This cuts down the capacity of the compressor one-hall but otherwise it does not change the proportions or the sctions so that the mechanical balance of the work is preserved throughout the complete revolution. If the pressure continu to rise the air opens the second air control which is adjusted to operate under higher pressure, and this unloads the adjacent ends or' the large cylinder and the small cylinder and renders the two cylinders for the time being completely ineffective. As the pr ssure falls the reverse action and order obtains and thus maintains the mechanical balance of work through- Out each re volurion.

ln this application the valve controls for the opposite ends of the some cylinder are shown and described as iurlepcnrlcnt and the air controls for the opposite ends of each cylinder are shown and described as work ing in sequence, or series, such an arrangement, how-- ver, is not claimed herein, for it is claimed in my copcnding application No. 375,431 filed .co-inciclently with this application.

The invention claimed is:-

J. The combination with a coinponnrl air compressor of means [or temporarily rendering ineffective intake valves oppoitc ends of the cylinders, marl means for actuatirl valve controls' on opposite ends of the cylinim tunoously, whereby the cy inders are unloaded proportionstely, substantially as specified.

2. The combination with :2 compound. air compressor of menus for temporarily rendering inelfective intake valves, and air controls for actuating the said valve controls at the complementary ends of the two cylinders simultaneously. substantially as specified 3. The combination with a compound air compressor of m nus for temporarily rendering ineffective the intake valves at opposite ends of both cylinders, and air con trols u 'rungcil to actuate the said valve controls on the opposi 4.- The combimnion with :1 compound nirycompvessor of means for controlling: the intake valves. and air controls actual-ed hy hc pressure produced by thccomni'essoi', and control opcr in: to actuate the valve controlling means at conipleuienun'y ends of both cylinders, and the col connecteti with the first air control onctuiiie the valve controlling means zit ends of both cylinders, substansccond all: and n il'nng t'rlly us specified.

The combination with a compound nir compressor 0: an independent valve cont'nl for each intzrkc. valve, air

ends of the cylinders simultaneously, suhstnn linlly a s'pccificd controls connected with each Gthtl and adapted 10 be actuated by thse pressure pl oducefi by the vumpn )1, one air uonuol being a'rangd to net upon the valve controls at cmnplememnr ends of U 3 Two uyiiuders and the other air control being arranged to act upon the :111 cnnircfls at the other mmplenmntnry ends of H11 two cylinders subsequently to the action 01 the nt. air control. substzm tinlly as specified.

6. The combination with :1 compound nir smnpyessor of Ned by air pl awry valve controls and u pwnpu, iinnmahy 52:1

sinnfiniiy us maximum :1 

